Air distribution to furnaces



1929- J. c. HAYES, JR 1,726,298

AIR DISTRIBUTION T0 FURNACES Filed March 6, 1926 wtmgpwm Patented Aug.27, 1929.

UNITED STATES 1,726,298 PATENT oFFicE.

JOHN C. HAYES, (TIL, OF CHICAGO, ILLINOIS, ASSIGNOR T0 FREYN ENGINEERINGCOIVI- PANY, OF CHICAGO, ILLINOIS, A CORPORATION OF MAINE.

AIR DISTRIBUTION TO FURNACES.

Application filed March 6,1926. Serial No. 92,773.

The present invention relates to air distribution to furnaces.

The present invention will be described with particular reference to thedistribution of air to a blast furnace. Great care and expense areinvolved in blast furnace practice in getting proper distribution of theore, coke and stone in the furnace stack for the purpose of securing auniform resistance to the up ward flow of air and the products ofcombustion. Many schemes have been used, with the view to bringing abouta proper stock distribution.

In spite of the expedients above referred to, a serious problem existsin blast furnace practice in securing a uniform air distribution. Thepresent invention contemplates a structure for automatically maintaininga fixed and predetermned flow of air to each of the tuyeres of a blastfurnace. According to the present invention, not only does the tuyerefurthest away from the bustle pipe connection to the hot blast main havethe same flow of air as the one closest to the connection, but theresult is also attained that the part of the furnace opposite any tuyerewhich may at any moment offer a greater resistance to the fiowof airwill be supplied its proper quota under a greater pressure.

' An object of the present invention is to pro vide a structure havingthe advantages immediately above referred to. I

A further object is to provide control means for the air supply of ablast furnace which is applicable to blast furnace construction as nowknown and'used and which will be reliable in operation.

A further object is to provide control means for the air supply of ablast furnace which will automatically maintain constant the ratio ofthe volume of air delivered by each tuyere compared to the total volumeof air delivered to said furnace regardless of conditions within thefurnace.

A further object is to provide control means for the air supply of ablast furnace which are adapted to provide variations in the ratio abovereferred to.

A further object is to provide an improved method of blast furnaceoperation.

Further objects will appear as the description proceeds.

Referring to the drawings- Figure 1 is a top plan view, partly insection, illustrating a blast furnace having a bustle pipe fordelivering air thereto; and Figure 2 is a diagrammatic viewillustrating'the principles of the present invention.

The numeral 10 indicates the wall of a blast furnace, which blastfurnace is provided with the tuyeres 1111. In the illustrated embodimentof the present invention, ten tuyeres are illustrated. The bustle pipe12 is provided for supplying air to the various tuyeres. For the purposeof connecting the bustle pipe 12 with the various tuyeres, a number ofpipes 1313 are provided, each leading to one of the tuyeres 11. Eachpipe 13 is provided with a valve 14 for controlling the resistance tothe flow of air through the corresponding pipe I 13. According to thepresent invention, said valves 14 are automatically controlled by meanswhich are indicated diagrammatically in Figure 2.

Referring to Figure 2, a plurality of con trol members 1515 areindicated. One of the control members 15 is provided for each of thepipes 13. For the purpose of this specification the connections ofonlyone of the control members 15 need be described, it being understoodthat the connections of the other control members 1515 to theircorresponding pipes 13 and their corresponding valves 14 aresubstantially the same.

, Each of the control members 15 is connected to be responsive to theflow of air through the corresponding pipe 13, which flow isproportional to the difference in pressure at two points in saidcorresponding pipe 13. Said points are indicated in the drawings by thenumerals 16 and 17 Said control members involve certain relay mechanism,which controls cables 18, one cable 18 being connected to each valve 14.Control members responsive to differential pressures in a pipe line arewell known in the art and may be readily purchased in the open marketwhich control members make use of Pitot tubes, orifice plates, Venturitubes and the like. Therefore a more detailed description of the controlmechanism is unnecessary in this specification. It will be understood,of course, that the present invention is not limited to the differentialpressure means for controlling the valves 1414L, it being within thescope of the present invention to use any preferred means responsive tothe flow of air through the individual pipes 1313 to control said valves1 l14. It is preferred to have means whereby the settings of the variouscontrol means may be adjusted. The drawing illustrates diagrammaticallyone form of adjusting means which may be used, it being understood thatany other preferred adjusting means may be used if desired. Theillustrated adjusting means includes an adjustable weight 18 which maybe disposed at different selectable distances from the fulcrum point ofthe lever 18 which controls the cable 18. The numeral 18 indicates arelay or movement multiplying means which may be interposed between eachlever 18 and its corresponding cable 18. Relays or movement multiplyingmeans suitable for the purpose are readily purchasable in the openmarket and need not be described in detail herein.

By Way of example, it may be assumed that the furnace illustrated isbeing supplied with a substantially constant number of cubic feet of airper minute. Normally, the throttling valve 14 above each of the tuyereswill be partly closed, so that there is a slight excess of pressure inthe bustle pipe over that required to pass said substantially constantnumber of cubic feet per minute to the furnace. In a perfectly workingfurnace, all. of the throttling valves 14 will be at certain midpositions, and the positions would probably be at greater closure forthe tuycres closest to the bustle pipe connection to the hot blast mainand in more open positions for the ones furthest away. These may beconsidered the normal positions of the valves. If it be assumed that onesection of the furnace in front of a certain tuyere begins to offer agreater resistance to the flow of air than the others, the controlmember 15 corresponding to said tuyere will immediatelyopen the corresponding throttle valve 14:, taking advantage of the excess pressurein the bustle pipe. Consequently a greater pressure of air will beapplied to that tuyere which had been considerably less than the maximumhot blast temperatures for fear of getting into furnace troubles broughtabout by faulty air dis tribution, faulty stock distribution, or faultyfurnace lines, will use the higher hot blast temperatures, whereby theeiliciency and capacity of the furnace will be very greatly in creased.

Though a preferred embodiment of the present invention has beendescribed in detail, many modifications will occur to those skilled inthe art. It is intended to cover all such modifications that fall withinthe scope of the appended claims.

What is claimed is 1. A blast furnace having a plurality of tuyeres, abustle pipe, pipe lines leading from said bustle pipe to said tuyeres,each of said pipe lines being provided with a valve and independentcontrol means for said valves, each of said means being responsive tothe flow of air through its corresponding pipe line forcontrolling itscorresponding valve to maintain substantially constant the volume of airdelivered through its corresponding pipe line..

2. The method of operating a blast furnace which comprises delivering asubstantially constant flow of air thereto under pressure in excess ofthat normally required at the tuyeres, distributing said air atuniformly spaced regions around said blast furnace, throttling said airto said various regions, and varying the extent of. said throttling inaccordance with the volume of air delivered to said various regions.

Signed at Chicago, Illinois, this 27 dayv of February, 1926.

JOHN C. HAYES, JR.

